The combination of an ethologically important, stereotyped behavior and specialized anatomy make avian song learning an ideal system in which to study the neural basis of motor learning. Auditory feedback from a bird's own vocal output is crucial for song acquisition, and song learning shares many important similarities with human speech learning. Furthermore, basal ganglia circuits that play an crucial role in song learning contribute during motor learning in mammals and have been implicated in human motor disorders such as Parkinson's disease. A database of songs will be constructed by recording from a large number of developing songbirds. All vocalizations produced during the period of song learning will be recorded, enabling theexamination of a complex learned behavior with unparalleled detail and completeness. Advanced statistical techniques will be used to analyze the detailed time course of song development, focusing on possible interactions between the development of individual song "syllables," song sequence, and song rhythm. A solid behavioral database will facilitate the interpretation of a wide range of experiments in the field, and will be used to develop more comprehensive models of song learning. By clarifying the principles governing vocal learning in songbirds, these models will yield insight into fundamental questions related to motor learning in humans.